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IB ESS Human population

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GURU CHARAN KUMAR
GURU CHARAN KUMAR

The document discusses various topics related to human population, including exponential population growth, crude birth rate, crude death rate, total fertility rate, infant mortality rate, and age structure of populations. It provides definitions and formulas for calculating crude birth rate, crude death rate, and rate of natural increase. Factors that affect population growth rates, such as advances in medicine and nutrition, are also examined.

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HUMAN POPULATION 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 1
•3.1.-Population Dynamics •3.1.1-Describe the nature and explain the implications of exponential growth in human populations. 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 2
This question is difficult to answer. •Estimates are usually based on food, but human agriculture limits assumptions on available amounts. •Human population growth rate has been growing more than exponentially. What is the carrying capacity of Earth for humans? 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 3
HUMAN POPULATION GROWTH 1999 1975 domestication of plants, animals 9000 B.C. (about 11,000 years ago) agriculturally based urban societies beginning of industrial, scientific revolutions 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 4
What is HUMAN POPULATION? •The total number of persons inhabiting a country, city, or any district or area. 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 5
What is Exponential growth? •Exponential population growth is when the birth rate is constant over a period of time and isn't limited by food or disease 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 6
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Measures of population changes are 1.Crude Birth Rate 2.Crude Death Rate 3.Rate of Natural Increase 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 8
What is CRUDE BIRTH RATE? •Crude birth rate is the childbirths per 1,000 people per year. This is a common measure of fertility for a given population. 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 9
•Therefore, the formula for crude birth rate is The crude birth rate = number of births per year x 1000 Total population Example. In 2007, there were 3,250 births in a city with population of 223,000. Therefore: CBR = 3,250 x1000 223,000 CBR =14.57 So, there were 14.57 births for every 1,000 people in the city. 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 10
•The crude birth rate could be of concern for particular countries who may be experiencing population decline, or for national governments who are worried about population growth rates that are higher than their country can sustain 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 11
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•The birth rate is usually the dominant factor in determining the rate of population growth. It depends on both the level of fertility and the age structure of the population. 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 16
CRUDE DEATH RATE •The death rate, while only a rough indicator of the mortality situation in a country, accurately indicates the current mortality impact on population growth. •This indicator is significantly affected by age distribution, and most countries will eventually show a rise in the overall death rate, in spite of continued decline in mortality at all ages, as declining fertility results in an aging population. 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 17
How to calculate Crude Death Rate? The crude death rate = number of death per year x 1000 Total population Example. In 2007, there were 4,000 death in a city with population of 2,000,000. Therefore: CBR = 4,000 x1000 2,000,000 CDR =2 So, there were 2 death for every 1,000 people in the city. 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 18
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Rates of Global Pop. Change •CBR (crude birth rate) = number of births per 1000 population –1990: 24 Today: 21.3 •CDR (crude death rate) = number of deaths per 1000 population –1990: 9 Today: 8.93 •Growth rate = birth rate - death rate (often in %) –1990: 1.5% Today: 1.3% –growth rates have come down 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 23
Special Kinds of Fertility and Mortality Rates •TFR (total fertility rate) = –number of children born to a woman during her reproductive years (or life time) –1990: 3.1 2000: 2.8 •IMR (infant mortality rate) = –infant deaths per 1000 live births (infant < 1 yr) –1990: 62 2000: 56 (1900: 200) 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 24
RECAP What is Human population? What is Crude Birth Rate? Formula What is Crude Death Rate? Formula What is Exponential growth? 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 25
Population, population change, growth rates •Population: number of persons •Population change: increase in the number of persons (per year) •Growth rates: rate of change (per year) 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 26
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Doubling Time Doubling time (T) = 70 . annual percentage rate Doubling time (T) = 70 . = 50 years 1.4 Doubling time = the number of years it would take a population to double its size at its current growth rate. 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 30
Doubling Time •Number of years in which a population reaches twice its size •Doubling time can be approximated using growth rates •doubling time = 70 : growth rate –rate: 1.4 doubling time: 49 –rate: 2.0 doubling time: 34.5 –rate: 0.5 doubling time: 138 –rate: -0.5 doubling time: ???? 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 31
How to calculate Rate of Natural Increase? •The rate of natural increase shows the rate at which people are added to a given population by births and deaths (ignoring migration). It is usually represented as follows: •Rate of Natural Increase Crude Birth Rate - Crude Death Rate 10 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 32
For example, Madagascar's crude birth rate 37.89 The crude death rate 7.97 37.89 -7.97 10 29.92 =2.992% 10 divide that by 10 and the result is 2.992%, Madagascar's rate of natural increase 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 33
Why has the world’s population grown at such different rates throughout history? Natural increase = births – deaths Net migration = immigrants – emigrants •Births •Deaths •Migration 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 34
What is mortality? •Mortality rate is a measure of the number of deaths (in general, or due to a specific cause) in a population, scaled to the size of that population, per unit of time 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 35
What is fertility rate ? •The total fertility rate (TFR), sometimes also called the fertility rate, period total fertility rate (PTFR) or total period fertility rate (TPFR) of a population is the average number of children that would be born to a woman over her lifetime •The number, which ranges from more than 7 children per woman in developing countries in Africa to around 1 child per woman in Eastern European and highly-developed Asian countries. 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 36
Births per woman < 2 2-2.9 3-3.9 4-4.9 5+ No Data Fertility Rates 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 37
What affects fertility rates? •Importance of children to labor force •Urbanization •Cost of raising and educating children •Education and employment options for women •Average age of marriage •Availability of pension plans •Availability of legal abortions •Availability of birth control •Religious beliefs, traditions and culture 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 38
What affects death rates? •Higher food supplies •Better nutrition •Improved medical and health technology •Improved sanitation •Safer water supplies 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 39
Indicators of overall health Growth = natural increase – net migration •Life expectancy •Infant mortality 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 40
Infant deaths per 1,000 live births <10 <10-35 <36-70 <71-100 <100+ Data not available 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 41
Population (2002) Population projected (2025) Infant mortality rate Life expectancy Fertility rate (TFR) %Population under age 15 % Population over age 65 Per capita GNI PPP (2000) 288 million 174 million 130 million 346 million 219 million 205 million 6.8 33 75 77 years 69 years 52 years 2.1 2.2 5.8 21% 33% 44% 13% 5% 3% $34,100 $7,300 $800 United States (highly developed) Brazil (moderately developed) Nigeria (less developed) © 2004 Brooks/Cole – Thomson Learning 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 42
Developed Countries 50 40 30 20 10 0 1775 1800 1850 1900 1950 2000 2050 Rate per 1,000 people Year Rate of natural increase Crude birth rate Crude death rate Rate of natural increase = crude birth rate – crude death rate © 2004 Brooks/Cole – Thomson Learning 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 43
Developing Countries 50 40 30 20 10 0 1775 1800 1850 1900 1950 2000 2050 Rate per 1,000 people Crude birth rate Rate of natural increase Crude death rate Year © 2004 Brooks/Cole – Thomson Learning 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 44
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Age Structure •Age structure—the proportion of the population in each age class. •Age structure influences whether a population will increase or decrease in size. 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 46
Age Structure •Countries that have high rates of growth usually have more young people than older people. •In contrast, countries that have slow growth or no growth usually have an even distribution of ages in the population. 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 47
Age Structure •Age structure can be graphed in a population pyramid, a type of double sided bar graph. 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 48
Age-Structure Diagrams 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 49
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Population Pyramids •Graphic device: bar graph •Shows the age and gender composition of a region •Horizontal axis: gender –male: left-hand female: right-hand –absolute number of people or % •Vertical axis: age –5-year or 10-year age groups 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 51
•A population pyramid, also called an age structure diagram, is a graphical illustration that shows the distribution of various age groups in a population which forms the shape of a pyramid when the population is growing. What is Population Pyramid? 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 52
•It show how many individuals are alive in different age groups in a country for a given year. •They also show how many are male and female. •Population numbers are always on the x-axis and age groups on the y-axis. •The overall stage can depict the stage of development of the country at a particular time. • LEDC’s tend to have expanding populations so they are wide at the bottom, whereas MEDC’s tend to have stationary or contracting pyramids as birth rates fall and individuals live longer. 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 53
Stage 1: High birth rate; rapid fall in each upward age group due high death rates; short life expectancy. Stage 2: High birth rate; fall in death rate as more living to middle age; slightly longer life expectancy. Stage 3: Declining birth rate; low death rate; more people living to old age. Stage 4: Low birth rate; low death rate; higher dependency ratio; longer life expectancy. 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 54
•It typically consists of two back-to-back bar graphs, with the population plotted on the X- axis and age on the Y-axis, one showing the number of males and one showing females in a particular population in five-year age groups •Males are conventionally shown on the left and females on the right, and they may be measured by raw number or as a percentage of the total population. 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 55
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Describe and explain the main features of the population pyramid below This population pyramid has a very wide base showing that there are a lot of babies born every year. This shows that there is a good medical service within the country. The different sectors from 5 - 9 up to 25 - 29 decreases very quickly and decreases even more quickly on the male side. This is good for the country, as there are fewer people to feed and educate. As the ages increase up through the pyramid, it gets narrower and narrower. This might be because as people get older they leave the country in search of a job or a better standard of living 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 57
3.1.3- •Analyse age/sex pyramids and diagrams showing demographic transition model 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 58
How can economic development help reduce birth rates? •Demographers have developed a hypothesis known as the DEMOGRAPHIC TRANSITION. •It states that as countries become industrialized, first death rates go down and then their birth rates decline. 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 59
AUGUST SUMMATIVE •Date :3.09.2013 •Total Marks :45(IB Format) •Time : 1 hour •Syllabus :Human Population •Unit :3.1.1, 3.1.2, 3.1.3 & 3.1.4 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 60
AUGUST FORMATIVE •Human Population Worksheet •Total Marks :40 •Will be given today •Due date : 29:08:2013 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 61
Demographic Transition 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 62
•The "Demographic Transition" is a model that describes population change over time. •The demographic transition model (DTM) is the transition from high birth and death rates to low birth and death rates as a country develops from a pre-industrial to an industrialized economic system. What is Demographic Transition? 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 63
Stage 1 - High Fluctuating Stage 2 - Early Expanding Stage 3 - Late Expanding Stage 4 - Low Fluctuating Stage 5- Only Possible in some countries FIVE STAGES IN DTM 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 64
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Birth Rate is high as a result of: 1.Lack of family planning 2.Need for workers in agriculture 3.Religious beliefs Death Rate is high because of: 1.High levels of disease 2.Famine 3.Lack of health care 4.War 5.Lack of education Stage One-DTM Both high birth rates and death rates fluctuate in the first stage of the population model giving a small population growth. There are many reasons for this: Typical of Britain in the 18th century and the Least Economically Developed Countries 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 66
•Birth Rate remains high. Death Rate is falling. Population begins to rise steadily. •Reasons Death Rate is falling as a result of: 1.Improved health care (e.g. Smallpox Vaccine) 2.Improved Hygiene (Water for drinking boiled) 3.Improved sanitation 4.Improved food production and storage •Typical of Britain in 19th century; Bangladesh; Nigeria STAGE TWO-DTM 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 67
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Birth Rate starts to fall. Death Rate continues to fall slowly. Population rising. Reasons: 1.Family planning available 2.Lower Infant Mortality Rate 3.Increased standard of living 4.Changing status of women •Typical of Britain in late 19th and early 20th century; China; Brazil STAGE THREE-DTM 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 72
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•Both birth rates and death rates remain low, fluctuating with 'baby booms' and epidemics of illnesses and disease. This results in a steady population. Typical of USA; Sweden; Japan; Britain STAGE FOUR-DTM 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 76
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•A stage 5 was not originally thought of as part of the DTM, but some northern countries are now reaching the stage where total population is declining where birth rates have dropped below death rates. • One such country is Germany, which has taken in foreign workers to fill jobs. STAGE FIVE-DTM 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 79
Area Birth Rate Reason Death Rate Reason LEDCs High No contraception Couples have many babies to compensate for the high death rate caused by poor health care Large families need to work on the land to contribute to family income Children look after old Religious reasons High Poor medical facilities Disease Poor nutrition High Infant mortality NICs High/ Decreasing People are used to having many children. Takes time for culture to change Changing status of women Decreasing As an economy develops money becomes available for better health care Housing improves Better childcare MEDCs Low Children are expensive People know their children are going to survive so they can keep their families small Widely available contraceptives Changing status of women Low Better health care Better standard of living 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 80
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What are the main factors that affect the growth of a population?  The main factors that make populations grow are births and immigration.(The action of coming to live permanently)  The main factors that make populations decrease are deaths and emigration.(moving from one place) 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 82
•Two types of population curve •S Population Curve •J Population Curve 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 83
TYPES OF POPULATION CURVE •Two modes of population growth. •J-Shape curve is also known as- Exponential curve occurs when there is no limit to population size. 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 84
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•S-Shape curve is also known as - Logistic curve shows the effect of a limiting factor •S-Sigmoid 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 86
What is S-Shaped Curve? •In S - shaped or sigmoid growth the population show an initial gradual increase in population size in an ecosystem, followed by an exponential increase and then a gradual decline to near constant level. 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 87
•In population of an ecosystem which factors determining the S shape curve? 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 88
The curve obtained by plotting growth and time is called a growth curve. It is a typical sigmoid or S- shaped curve. 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 89
What is J shaped? •A curve on a graph that records the situation in which, in a new environment, the population density of an organism increases rapidly but then stops abruptly as environmental resistance •It may be summarized mathematically as: I. dN/dt = rN (with a definite limit on N) II.where N is the number of individuals in the population, t is time, and III.r is a constant representing the rate of increase for the organism concerned. 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 90
•The growth of population is measured as increase in its size over a period of time and populations show characteristic patterns of growth with time. • These patterns are known as population growth forms. 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 91
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What is Carrying Capacity ? •Carrying Capacity is the maximum number of a species or load that can be sustainably supported by a given environment i.e without destroying the stock •Population remain stable when the death rate and the birth rate are equal and so there is no net gain or reduction in population size 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 93
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Semester Syllabus •Systems & Models •The Ecosystem •Conservation & Biodiversity •Global Warming •Human Population 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 95

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IB ESS Human population

  • 1. HUMAN POPULATION 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 1
  • 2. •3.1.-Population Dynamics •3.1.1-Describe the nature and explain the implications of exponential growth in human populations. 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 2
  • 3. This question is difficult to answer. •Estimates are usually based on food, but human agriculture limits assumptions on available amounts. •Human population growth rate has been growing more than exponentially. What is the carrying capacity of Earth for humans? 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 3
  • 4. HUMAN POPULATION GROWTH 1999 1975 domestication of plants, animals 9000 B.C. (about 11,000 years ago) agriculturally based urban societies beginning of industrial, scientific revolutions 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 4
  • 5. What is HUMAN POPULATION? •The total number of persons inhabiting a country, city, or any district or area. 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 5
  • 6. What is Exponential growth? •Exponential population growth is when the birth rate is constant over a period of time and isn't limited by food or disease 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 6
  • 7. 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 7
  • 8. Measures of population changes are 1.Crude Birth Rate 2.Crude Death Rate 3.Rate of Natural Increase 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 8
  • 9. What is CRUDE BIRTH RATE? •Crude birth rate is the childbirths per 1,000 people per year. This is a common measure of fertility for a given population. 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 9
  • 10. •Therefore, the formula for crude birth rate is The crude birth rate = number of births per year x 1000 Total population Example. In 2007, there were 3,250 births in a city with population of 223,000. Therefore: CBR = 3,250 x1000 223,000 CBR =14.57 So, there were 14.57 births for every 1,000 people in the city. 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 10
  • 11. •The crude birth rate could be of concern for particular countries who may be experiencing population decline, or for national governments who are worried about population growth rates that are higher than their country can sustain 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 11
  • 12. 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 12
  • 13. 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 13
  • 14. 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 14
  • 15. 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 15
  • 16. •The birth rate is usually the dominant factor in determining the rate of population growth. It depends on both the level of fertility and the age structure of the population. 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 16
  • 17. CRUDE DEATH RATE •The death rate, while only a rough indicator of the mortality situation in a country, accurately indicates the current mortality impact on population growth. •This indicator is significantly affected by age distribution, and most countries will eventually show a rise in the overall death rate, in spite of continued decline in mortality at all ages, as declining fertility results in an aging population. 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 17
  • 18. How to calculate Crude Death Rate? The crude death rate = number of death per year x 1000 Total population Example. In 2007, there were 4,000 death in a city with population of 2,000,000. Therefore: CBR = 4,000 x1000 2,000,000 CDR =2 So, there were 2 death for every 1,000 people in the city. 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 18
  • 19. 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 19
  • 20. 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 20
  • 21. 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 21
  • 22. 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 22
  • 23. Rates of Global Pop. Change •CBR (crude birth rate) = number of births per 1000 population –1990: 24 Today: 21.3 •CDR (crude death rate) = number of deaths per 1000 population –1990: 9 Today: 8.93 •Growth rate = birth rate - death rate (often in %) –1990: 1.5% Today: 1.3% –growth rates have come down 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 23
  • 24. Special Kinds of Fertility and Mortality Rates •TFR (total fertility rate) = –number of children born to a woman during her reproductive years (or life time) –1990: 3.1 2000: 2.8 •IMR (infant mortality rate) = –infant deaths per 1000 live births (infant < 1 yr) –1990: 62 2000: 56 (1900: 200) 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 24
  • 25. RECAP What is Human population? What is Crude Birth Rate? Formula What is Crude Death Rate? Formula What is Exponential growth? 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 25
  • 26. Population, population change, growth rates •Population: number of persons •Population change: increase in the number of persons (per year) •Growth rates: rate of change (per year) 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 26
  • 27. 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 27
  • 28. 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 28
  • 29. 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 29
  • 30. Doubling Time Doubling time (T) = 70 . annual percentage rate Doubling time (T) = 70 . = 50 years 1.4 Doubling time = the number of years it would take a population to double its size at its current growth rate. 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 30
  • 31. Doubling Time •Number of years in which a population reaches twice its size •Doubling time can be approximated using growth rates •doubling time = 70 : growth rate –rate: 1.4 doubling time: 49 –rate: 2.0 doubling time: 34.5 –rate: 0.5 doubling time: 138 –rate: -0.5 doubling time: ???? 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 31
  • 32. How to calculate Rate of Natural Increase? •The rate of natural increase shows the rate at which people are added to a given population by births and deaths (ignoring migration). It is usually represented as follows: •Rate of Natural Increase Crude Birth Rate - Crude Death Rate 10 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 32
  • 33. For example, Madagascar's crude birth rate 37.89 The crude death rate 7.97 37.89 -7.97 10 29.92 =2.992% 10 divide that by 10 and the result is 2.992%, Madagascar's rate of natural increase 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 33
  • 34. Why has the world’s population grown at such different rates throughout history? Natural increase = births – deaths Net migration = immigrants – emigrants •Births •Deaths •Migration 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 34
  • 35. What is mortality? •Mortality rate is a measure of the number of deaths (in general, or due to a specific cause) in a population, scaled to the size of that population, per unit of time 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 35
  • 36. What is fertility rate ? •The total fertility rate (TFR), sometimes also called the fertility rate, period total fertility rate (PTFR) or total period fertility rate (TPFR) of a population is the average number of children that would be born to a woman over her lifetime •The number, which ranges from more than 7 children per woman in developing countries in Africa to around 1 child per woman in Eastern European and highly-developed Asian countries. 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 36
  • 37. Births per woman < 2 2-2.9 3-3.9 4-4.9 5+ No Data Fertility Rates 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 37
  • 38. What affects fertility rates? •Importance of children to labor force •Urbanization •Cost of raising and educating children •Education and employment options for women •Average age of marriage •Availability of pension plans •Availability of legal abortions •Availability of birth control •Religious beliefs, traditions and culture 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 38
  • 39. What affects death rates? •Higher food supplies •Better nutrition •Improved medical and health technology •Improved sanitation •Safer water supplies 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 39
  • 40. Indicators of overall health Growth = natural increase – net migration •Life expectancy •Infant mortality 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 40
  • 41. Infant deaths per 1,000 live births <10 <10-35 <36-70 <71-100 <100+ Data not available 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 41
  • 42. Population (2002) Population projected (2025) Infant mortality rate Life expectancy Fertility rate (TFR) %Population under age 15 % Population over age 65 Per capita GNI PPP (2000) 288 million 174 million 130 million 346 million 219 million 205 million 6.8 33 75 77 years 69 years 52 years 2.1 2.2 5.8 21% 33% 44% 13% 5% 3% $34,100 $7,300 $800 United States (highly developed) Brazil (moderately developed) Nigeria (less developed) © 2004 Brooks/Cole – Thomson Learning 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 42
  • 43. Developed Countries 50 40 30 20 10 0 1775 1800 1850 1900 1950 2000 2050 Rate per 1,000 people Year Rate of natural increase Crude birth rate Crude death rate Rate of natural increase = crude birth rate – crude death rate © 2004 Brooks/Cole – Thomson Learning 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 43
  • 44. Developing Countries 50 40 30 20 10 0 1775 1800 1850 1900 1950 2000 2050 Rate per 1,000 people Crude birth rate Rate of natural increase Crude death rate Year © 2004 Brooks/Cole – Thomson Learning 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 44
  • 45. 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 45
  • 46. Age Structure •Age structure—the proportion of the population in each age class. •Age structure influences whether a population will increase or decrease in size. 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 46
  • 47. Age Structure •Countries that have high rates of growth usually have more young people than older people. •In contrast, countries that have slow growth or no growth usually have an even distribution of ages in the population. 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 47
  • 48. Age Structure •Age structure can be graphed in a population pyramid, a type of double sided bar graph. 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 48
  • 49. Age-Structure Diagrams 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 49
  • 50. 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 50
  • 51. Population Pyramids •Graphic device: bar graph •Shows the age and gender composition of a region •Horizontal axis: gender –male: left-hand female: right-hand –absolute number of people or % •Vertical axis: age –5-year or 10-year age groups 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 51
  • 52. •A population pyramid, also called an age structure diagram, is a graphical illustration that shows the distribution of various age groups in a population which forms the shape of a pyramid when the population is growing. What is Population Pyramid? 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 52
  • 53. •It show how many individuals are alive in different age groups in a country for a given year. •They also show how many are male and female. •Population numbers are always on the x-axis and age groups on the y-axis. •The overall stage can depict the stage of development of the country at a particular time. • LEDC’s tend to have expanding populations so they are wide at the bottom, whereas MEDC’s tend to have stationary or contracting pyramids as birth rates fall and individuals live longer. 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 53
  • 54. Stage 1: High birth rate; rapid fall in each upward age group due high death rates; short life expectancy. Stage 2: High birth rate; fall in death rate as more living to middle age; slightly longer life expectancy. Stage 3: Declining birth rate; low death rate; more people living to old age. Stage 4: Low birth rate; low death rate; higher dependency ratio; longer life expectancy. 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 54
  • 55. •It typically consists of two back-to-back bar graphs, with the population plotted on the X- axis and age on the Y-axis, one showing the number of males and one showing females in a particular population in five-year age groups •Males are conventionally shown on the left and females on the right, and they may be measured by raw number or as a percentage of the total population. 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 55
  • 56. 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 56
  • 57. Describe and explain the main features of the population pyramid below This population pyramid has a very wide base showing that there are a lot of babies born every year. This shows that there is a good medical service within the country. The different sectors from 5 - 9 up to 25 - 29 decreases very quickly and decreases even more quickly on the male side. This is good for the country, as there are fewer people to feed and educate. As the ages increase up through the pyramid, it gets narrower and narrower. This might be because as people get older they leave the country in search of a job or a better standard of living 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 57
  • 58. 3.1.3- •Analyse age/sex pyramids and diagrams showing demographic transition model 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 58
  • 59. How can economic development help reduce birth rates? •Demographers have developed a hypothesis known as the DEMOGRAPHIC TRANSITION. •It states that as countries become industrialized, first death rates go down and then their birth rates decline. 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 59
  • 60. AUGUST SUMMATIVE •Date :3.09.2013 •Total Marks :45(IB Format) •Time : 1 hour •Syllabus :Human Population •Unit :3.1.1, 3.1.2, 3.1.3 & 3.1.4 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 60
  • 61. AUGUST FORMATIVE •Human Population Worksheet •Total Marks :40 •Will be given today •Due date : 29:08:2013 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 61
  • 62. Demographic Transition 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 62
  • 63. •The "Demographic Transition" is a model that describes population change over time. •The demographic transition model (DTM) is the transition from high birth and death rates to low birth and death rates as a country develops from a pre-industrial to an industrialized economic system. What is Demographic Transition? 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 63
  • 64. Stage 1 - High Fluctuating Stage 2 - Early Expanding Stage 3 - Late Expanding Stage 4 - Low Fluctuating Stage 5- Only Possible in some countries FIVE STAGES IN DTM 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 64
  • 65. 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 65
  • 66. Birth Rate is high as a result of: 1.Lack of family planning 2.Need for workers in agriculture 3.Religious beliefs Death Rate is high because of: 1.High levels of disease 2.Famine 3.Lack of health care 4.War 5.Lack of education Stage One-DTM Both high birth rates and death rates fluctuate in the first stage of the population model giving a small population growth. There are many reasons for this: Typical of Britain in the 18th century and the Least Economically Developed Countries 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 66
  • 67. •Birth Rate remains high. Death Rate is falling. Population begins to rise steadily. •Reasons Death Rate is falling as a result of: 1.Improved health care (e.g. Smallpox Vaccine) 2.Improved Hygiene (Water for drinking boiled) 3.Improved sanitation 4.Improved food production and storage •Typical of Britain in 19th century; Bangladesh; Nigeria STAGE TWO-DTM 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 67
  • 68. 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 68
  • 69. 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 69
  • 70. 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 70
  • 71. 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 71
  • 72. Birth Rate starts to fall. Death Rate continues to fall slowly. Population rising. Reasons: 1.Family planning available 2.Lower Infant Mortality Rate 3.Increased standard of living 4.Changing status of women •Typical of Britain in late 19th and early 20th century; China; Brazil STAGE THREE-DTM 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 72
  • 73. 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 73
  • 74. 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 74
  • 75. 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 75
  • 76. •Both birth rates and death rates remain low, fluctuating with 'baby booms' and epidemics of illnesses and disease. This results in a steady population. Typical of USA; Sweden; Japan; Britain STAGE FOUR-DTM 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 76
  • 77. 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 77
  • 78. 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 78
  • 79. •A stage 5 was not originally thought of as part of the DTM, but some northern countries are now reaching the stage where total population is declining where birth rates have dropped below death rates. • One such country is Germany, which has taken in foreign workers to fill jobs. STAGE FIVE-DTM 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 79
  • 80. Area Birth Rate Reason Death Rate Reason LEDCs High No contraception Couples have many babies to compensate for the high death rate caused by poor health care Large families need to work on the land to contribute to family income Children look after old Religious reasons High Poor medical facilities Disease Poor nutrition High Infant mortality NICs High/ Decreasing People are used to having many children. Takes time for culture to change Changing status of women Decreasing As an economy develops money becomes available for better health care Housing improves Better childcare MEDCs Low Children are expensive People know their children are going to survive so they can keep their families small Widely available contraceptives Changing status of women Low Better health care Better standard of living 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 80
  • 81. 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 81
  • 82. What are the main factors that affect the growth of a population?  The main factors that make populations grow are births and immigration.(The action of coming to live permanently)  The main factors that make populations decrease are deaths and emigration.(moving from one place) 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 82
  • 83. •Two types of population curve •S Population Curve •J Population Curve 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 83
  • 84. TYPES OF POPULATION CURVE •Two modes of population growth. •J-Shape curve is also known as- Exponential curve occurs when there is no limit to population size. 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 84
  • 85. 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 85
  • 86. •S-Shape curve is also known as - Logistic curve shows the effect of a limiting factor •S-Sigmoid 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 86
  • 87. What is S-Shaped Curve? •In S - shaped or sigmoid growth the population show an initial gradual increase in population size in an ecosystem, followed by an exponential increase and then a gradual decline to near constant level. 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 87
  • 88. •In population of an ecosystem which factors determining the S shape curve? 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 88
  • 89. The curve obtained by plotting growth and time is called a growth curve. It is a typical sigmoid or S- shaped curve. 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 89
  • 90. What is J shaped? •A curve on a graph that records the situation in which, in a new environment, the population density of an organism increases rapidly but then stops abruptly as environmental resistance •It may be summarized mathematically as: I. dN/dt = rN (with a definite limit on N) II.where N is the number of individuals in the population, t is time, and III.r is a constant representing the rate of increase for the organism concerned. 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 90
  • 91. •The growth of population is measured as increase in its size over a period of time and populations show characteristic patterns of growth with time. • These patterns are known as population growth forms. 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 91
  • 92. 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 92
  • 93. What is Carrying Capacity ? •Carrying Capacity is the maximum number of a species or load that can be sustainably supported by a given environment i.e without destroying the stock •Population remain stable when the death rate and the birth rate are equal and so there is no net gain or reduction in population size 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 93
  • 94. 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 94
  • 95. Semester Syllabus •Systems & Models •The Ecosystem •Conservation & Biodiversity •Global Warming •Human Population 8/22/2013 Guru ESS-TOPIC HUMAN POPULATION 95